Current year goals: 1) Evaluation of cytosol of normal endometrium for a possible androgen receptor, and study of its relation to the binding of progesterone and synthetic progestins. 2) Testing of endometrial cells now growing in tissue culture for the presence of steroid hormone receptors by methods devised specifically for this purpose. 3) Continued attempt to establish a human endometrial cancer cell line by implantation of cells derived from endometrial cancers and now growing in tissue culture into nude mice. 4) Continuation of the search for specific proteins of the endometrial washings obtained in vivo and in incubations of endometrial tissue in vitro with labeled leucine. 5) The search for a hypothetical clinical syndrome of progesterone-resistant endometrium.